1. Field of the Invention
The present invention relates to a digital camera and a switch device, and more particularly, to the digital camera including the switch device which is provided with a knob having a shaft portion adapted to be rotatably inserted, and the switch device itself.
2. Description of the Related Art
A switch device which is provided with a knob having a shaft portion adapted to be rotatably inserted has been conventionally known (See JP-A-10-208586 and JP-UM-A-61-65633, for example).
In the abovementioned JP-A-10-208586, there is disclosed a first example of the conventional switch device, in which cut-out parts in a sector shape concentric with a rotation center of a joggle knob are formed in an area of a front panel for supporting the joggle knob, and locking claws of the joggle knob are inserted into the cut-outs to be locked. This switch device disclosed in JP-A-10-208586 includes two inclined plates which are arranged at an inner face side of the front panel along a rotation orbit of the locking claws of the joggle knob and adapted to be pushed toward a back face side depending on rotary positions of the joggle knob, and an operation board which is positioned in the back face side of the two inclined plates and provided with a push switch.
In the above mentioned JP-UM-A-61-65633, there is disclosed a second example of the conventional switch device in which an electrically conductive plate is attached to a knob made of resin to be integrated therewith, and locking claws of the knob are engaged with round holes in a printed board. In the switch device disclosed in JP-UM-A-61-65633, a tongue piece of the electrically conductive plate is press fitted into a mounting part of the knob and bent, whereby the electrically conductive plate and the knob are integrated.
In the specification of the present application, as one example of the switch device, a switch device in a digital camera will be described.
FIG. 8 is a perspective view of a digital camera provided with a conventional switch device. FIG. 9 is an exploded perspective view showing a part of the digital camera having the conventional switch device which is shown in FIG. 8. FIG. 10 is a bottom view of the conventional switch device in the digital camera which is shown in FIG. 9. FIG. 11 is a sectional view of the conventional switch device in the digital camera which is shown in FIG. 9, taken along a line 300-300. Referring first to FIGS. 8 to 11, a structure of a digital camera 100 provided with the conventional switch device will be described.
In the digital camera 100 provided with the conventional switch device, as shown in FIG. 8, a switch device 115 is mounted on a switch mounting part 111 which is provided on an upper face of a body 110. This switch device 115 is provided for the purpose of switching over various functions of the digital camera 100. The switch device 115 includes, as shown in FIG. 9, the switch mounting part 111 of the body 110, a knob 120 having a shaft portion 121, a leaf spring member 130, a securing member 140, a screw 150 for fixing the shaft portion, a contact part 160, a screw 170 for fixing the contact part, and a switch board 180.
The switch mounting part 111 has a shaft portion insertion hole 111a, and a leaf spring mounting part 111b. The shaft portion 121 of the knob 120 is rotatably inserted into this shaft portion insertion hole 111a. The leaf spring mounting part 111b is provided so as to surround a circumference of the shaft portion insertion hole 111a. This leaf spring mounting part 111b is provided for the purpose of securing the leaf spring member 130.
The knob 120 is so designed as to switch over the functions of the digital camera 100 through its rotation. The shaft portion 121 of the knob 120 is provided with a female screw part 122 on a lower face thereof, as shown in FIG. 10. This female screw part 122 is provided for the purpose of fitting the shaft portion fixing screw 150, as shown in FIG. 11. Moreover, as shown in FIGS. 10 and 11, recesses 123 are formed on an inner peripheral face of the knob 120 at the lower face side thereof. These recesses 123 are so designed as to be engaged with the leaf spring member 130 at every determined rotation angle, when the knob 120 is rotated. The leaf spring member 130 is mounted on the leaf spring mounting part 111b of the switch mounting part 111 in a fixed manner, as shown in FIGS. 9 and 11. A tip end portion 131 of the leaf spring member 130 is so designed as to be engaged with the recesses 123 of the knob 120, when the knob 120 is rotated. In this manner, rotation angle positions of the knob 120 will be maintained at every determined rotation angle.
The securing member 140 is provided so as to come into contact with the body 110 from an inner face side of the body 110. The securing member 140 has a screw insertion hole 141. As shown in FIG. 11, the shaft portion fixing screw 150 is fitted into the female screw 122 of the knob 120 through the screw insertion hole 141 of the securing member 140 from the inner face side of the body 110. The contact part 160 is fixed to a lower face of the securing member 140 by means of the contact part fixing screw 170.
The contact part 160 is provided so as to come into contact with the switch board 180. This contact part 160 is so designed as to rotate along with the securing member 140 around the shaft portion 121 of the knob 120 as a rotation center, when the knob is rotated. As shown in FIG. 9, the switch board 180 which comes into contact with the contact part 160 is provided with an electrically conductive part 181, at a position corresponding to an orbit of the contact part 160 which rotates around the shaft portion 121 of the knob 120 as the rotation center. This electrically conductive part 181 has a plurality of divided arc-shaped patterns. Because of a plurality of the divided arc-shaped patterns of the electrically conductive part 181, it is possible to switch over contacts at every position of the determined rotation angle, when the knob 120 is rotated.
However, in the digital camera 100 provided with the conventional switch device 115 which is shown in FIG. 9, fixation of the knob 120 to the body 110 has been performed employing the securing member 140 and the shaft portion fixing screw 150. Fixation of the contact part 160 to the securing member 140 has been performed by means of the contact part fixing screw 170. Consequently, there has been a problem that components have increased in number, in the conventional switch device 115 in the digital camera 100. Moreover, there has been another problem that assembling steps have increased in number, because there have been two screwing parts which would take a considerable assembling time.
In the conventional switch device according to the first conventional example disclosed in the above described JP-A-10-208586, the joggle knob is constructed in such a manner that it does not directly press the push switch on the operation board, but it presses two push switches byway of the two inclined plates. In this case, because one push switch has a faculty of switching over only one kind of function, there has been such inconvenience that many inclined plates and many push switches have become necessary, in order to construct the switch device so that it may have a faculty of switching over many functions. Therefore, there has been a problem also in the switch device disclosed in this JP-A-10-208586, that the number of components have increased, in the same manner as in the digital camera 100 provided with the conventional switch device 115 which is shown in FIG. 9.
On the other hand, in the conventional switch device according to the second example which is disclosed in the above described JP-UM-A-61-65633, there has been a problem that assembling steps have been complicated, because on occasion of mounting the electrically conductive plate to the mounting part of the knob, it has been necessary to press-fit the tongue piece of the electrically conductive plate into an end part of the mounting part and to bend it.